In air conditioning systems of the above mentioned type, a separate air distributor system is generally associated with each air conditioning zone. Each air distributor system is connected on the one hand to the air conditioning plant, and on the other hand to an air tap system through a controllable mixing valve. A temperature control is provided for each air distributor system. For example, by appropriately controlling the mixing valve in each air distributor system, the temperature of the air delivered from each distributor system is a respective mixed temperature T.sub.m =t+.DELTA.t. The delivered air consists of air provided by the air conditioning plant at a predetermined base temperature t admixed with hot air from the air tap system to achieve a temperature increment .DELTA.t and result in the mixed temperature T.sub.m. Furthermore, a temperature regulation is generally provided for each air conditioning zone.
It is especially important in passenger aircraft to maintain a prescribed cabin temperature for reasons of comfort for the passengers. Because the seating density and therewith the thermal load differs among the various passenger classes within an aircraft cabin, a separate temperature regulation system is required in each passenger class, whereby the desired nominal temperature is to be selected or input by means of a temperature selector. Thus, a passenger cabin is always separated into several air conditioning zones, each of which corresponds to a separate passenger class. Each of the air conditioning zones comprises its own temperature regulation or control. In aircraft using known air conditioning systems of the above described type, once the passenger cabin has been divided into separate air conditioning zones, it is generally impossible to alter or reallocate the air conditioning zones, i.e. to move the boundaries between air conditioning zones, for example. If a reallocation of the air conditioning zones is possible at all, it requires the physical or mechanical alteration and restructuring of the air delivery system.